Treatment of feldspar concentrates having hydrophobic characteristics



Patented May 1, 195T TREATMENT OF FELDSPAR CONCENTRATES HAVINGHYDROPHOBIC CHARACTERIS- TICS James A. Barr, Jr., Evanston, Ill.,assignor to Armour and Company, Chicago, 111., a corporation of IllinoisNo Drawing. Application March 16, 1949, Serial No. 81,847

7 Claims. (01. 23-110) This invention relates to the treatment offeldspar concentrates having hydrophobic characteristics for removal ofsuch characteristics. The invention is particularly useful in theremoval of hydrophobic films formed on feldspar concentrate by frothflotation. .1 In the production of feldspar concentrate by frothflotation, nitrogenous compounds are employed which introduce ahydrophobic film onto the concentrate. Later, in castin operations thehydrophobic film causes frothing of a casting slip which includes suchfeldspar flotation concentrate. Such frothin has sometimes caused therejection of feldspar flotation concentrate for use in the mold castingprocesses of the ceramic industry.

In casting operations, it is customary to form a casting slip consistingof a mixture of feldspar, quartz and clays (both primary and secondary).This material is mixed with Water and alkali to deflocculate the slip.The slip is poured into a porous mold and is left for a predeterminedtime. The water is drawn into the mold and minerals are built up as abody inside the mold. Later,

the mold parts are usually separated to free the cast body.

In the forming of the casting slip, as above described, it is found thatthe feldspar flotation concentrate, by reason of its hydrophobic filmcauses serious frothing.

An object of the present invention is to provide a simple method andmeans for removing hydrophobic film from feldspar concentrates wherebyfrothing does not occur in the casting slip forming step. Yet anotherobject is to provide a simple operation whereby feldspar concentrateshaving hydrophobic characteristics are modified so as to no longer causefrothing in the forming of a casting slip. Other specific objects andadvantages will appear as the specification proceeds.

I have discovered that by mixing a mineral having a high base exchangecapacity with feldspar concentrates having such hydrophobiccharacteristics, the hydrophobic film is removed from the feldspar to asatisfactory degree. The organo-colloidal mineral complex can beisolated and readily removed. The process is effective with feldsparconcentrates which have been treated with any nitrogenous compounds thatintroduce hydrophobic characteristics into the concentrates. Suchnitrogenous materials producing these results include high molecularweight amines, high molecular weight amine salts derived from fattyacids, such as the amine acetate and amine hydrochloride salts. Othernitrogenous materials are glyoxalidines, rosinamine acetate, tallowtrimethyl ammonium chloride, etc. It will be un-. derstood that thehydrophobic film is formed through the use of a large number of suchnitrogenous compounds and presents the problem to the solution of whichthe process of the present invention is directed.

In carrying out my invention, the feldspar concentrate having thehydrophobic film or characteristic is treated by agitation with a smallamount of a mineral having a high base exchange capacity preferably longenough for the frothing to disappear. The treating mineral and the filmform a colloidal body which may be decanted or otherwise readilyremoved. Kaolinite and bentonite provide satisfactory treatingmaterials. They may be-used in the proportions of from 1 to 10 poundsfor each ton of concentrate being treated. I prefer to use about 2 to 5pounds of the treating mineral per ton of concentrate.

The colloidal material containing the bentonite or kaolinite, etc., incounter-current washing is decanted from the top of the liquid bodywhile the concentrate minerals are withdrawn from the lower portion ofthe body. Ready removal is effected in a hydroclassifier in which theconcentrate passes through a vessel having an open bottom and in which astream of water is introduced so as to overflow at the top. Thecolloidal material overflows and is thus separated from the concentrateand the recovered concentrate may then be employed in forming castingslips with no resulting frothing.

Specific examples of the process may be set out as follows:

Example I North Carolina feldspar containing Muscovite mica, biotitemica, garnet, sodium and potassium feldspars, and quartz was separatedinto a mica fraction, a garnet fraction, a feldspar fraction, and aquartz fraction. In the feldspar and quartz separation .35 pound of anamine acetate derived from tallow fatty acid (Armac T) was used per tonof the concentrate and also hydrofluoric acid was employed to depressthe quartz. Pine oil was used to form a froth. The feldspar concentrateobtained when employed in forming a casting slip, produced frothing ofthe slip. To eliminate the hydrophobic film formed in the feldsparconcentrate, the feldspar concentrate was agitated with 2 pounds ofbentonite per ton of concentrate forlabout 5 minutes, after which thefroth disappeared. The colloidal material produced by this treatment wasthen removed by decanting and the feldspar concentrate was washedrelatively free of colloidal material. After drying, the feldspar sotreated was found to be water wettable upon agitation and did not causefroth to form when aerated or mixed with other minerals to form acastingslip.

Example II In a similar treatment of feldspar in which .4 pound of amineacetate (Armac T), 0.8,pound of a hydrocarbon, .1-.2 pound of pine oiland 1-1 pounds of hydrofluoric acid per ton of feldspar concentrate wasused and a hydrophobic film characteristic developed in the feldsparconcentrate. Feldspar was agitated with 5 pounds of kaolinite for about5 minutes when the froth disappeared. The material was then put-througha hydroclassifier in which the feldspar concentrate was washed free ofcolloidal material and the colloidal material containing kaolinite andthe hydrophobic film was removed from the top of the classifier. Thefeldspar recovered in the above process was found to be water wettableand did not cause froth when aerated or mixed with other minerals toform a casting slip.

Example III In a treatment of feldspar with amine hydrochloride derivedfrom tallow fatty acid in percentages varying from .25 to .45, ahydrophobic film was introduced into the feldspar concentrate. Theconcentrate was treated with varying amounts of bentonite and kaolinitebetween 2 and 5 pounds per ton of concentrate and agitation kept upuntil froth disappeared. The resulting colloidal material was removedand'the washed feldspar concentrate was found to be water Wettable anddid not cause frothing in the forming of the casting slip.

The operation involves very little expense because of the low amount oftreating mineral required and because the colloidal material is removedso readily in a washing or desliming operation normal to millingoperations.

While in the foregoing specification, I have set out steps of theprocess in considerable detail for the purpose of illustratingembodiments thereof, it will be understood that such detail may bevaried widely by those skilled in the art without departing from thespirit of my invention.

I claim:

1. In a process for removing hydrophobic film from feldspar concentratestreated with filmforming nitrogenous material in froth flotation,

the steps of agitating the feldspar concentrates in water with a mineralhaving a high base exchange capacity until frothing disappears, andremoving the resulting colloidal material.

2. In a process for removinghydrophobic film from feldspar concentratestreated with hydrophobic-film-forming nitrogenous materials, the

steps of agitating the feldspar concentrates in water with a mineralhaving a high base exchange capacity until the frothing disappears, andthen removing the resulting colloidal material.

3. In a processfor removing hydrophobic film produced in feldsparconcentrates by the action of treating nitrogenous materials, the stepsof agitating the feldspar concentrates in water with a. small amount ofmineral having a high base exchange capacity until the frothingdisappears and a colloidal body is produced consisting of said materialand said. film, and decanting the i colloidal-material.

4. In a process for removing hydrophobic film from feldspar concentratesproduced by nitrogenous treating materials, the steps of agitating thefeldspar concentrates in water "with ;.from about 2 to 5 pounds of amineral having a high base exchange capacity per .ton of concentrate,and removing the resulting colloidal material.

5. In a process for removing hydrophobic film from feldspar concentratesin which such film is produced through the use of nitrogenous treatingmaterials, the steps of agitating the feldspar concentrates in Waterwith about 2-5 pounds of bentonite per ton of concentrate, and removingthe resulting colloidal material.

6. In a process for removing hydrophobic film from feldspar concentratesin which such film is produced through the use of nitrogenous treat- Noreferences cited.

1. IN A PROCESS FOR REMOVING HYDROPHOBIC FILM FROM FELDSPAR CONCENTRATESTREATED WITH FILMFORMING NITROGENOUS MATERIAL IN FROTH FLOTATION, THESTEPS OF AGITATING THE FELDSPAR CONCENTRATES IN WATER WITH A MINERALHAVING A HIGH BASE EXCHANGE CAPACITY UNTIL FROTHING DISAPPEARS, ANDREMOVING THE RESULTING COLLOIDAL MATERIAL.